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The Sabatier principle is widely explored in heterogeneous catalysis, graphically depicted in volcano plots. The most desirable activity is located at the peak of the volcano, and further advances in activity past this optimum are possible by designing a catalyst that circumvents the limitation entailed by the Sabatier principle. Herein, by density functional theory calculations, we discovered an unusual Sabatier principle on high entropy alloy (HEA) surface, distinguishing the "just right" (ΔGH* = 0 eV) in the Sabatier principle of hydrogen evolution reaction (HER). A new descriptor was proposed to design HEA catalysts for HER. As a proof-of-concept, the synthesized PtFeCoNiCu HEA catalyst endows a high catalytic performance for HER with an overpotential of 10.8 mV at −10 mA cm−2 and 4.6 times higher intrinsic activity over the state-of-the-art Pt/C. Moreover, the unusual Sabatier principle on HEA catalysts can be extended to other catalytic reactions. The advancement of high entropy alloy development is both rapid and challenging. Here, the authors discover an unusual Sabatier principle operating on the high entropy alloy surface, which leads to a notable enhancement in catalytic activity for hydrogen evolution reactions. [ABSTRACT FROM AUTHOR]

Yarn-shaped supercapacitors are favored due to their small size, high specific capacitance, and light weight. Herein, we reported a distinctive type of ply twist yarn supercapacitor by in situ polymerization of pyrrole on carbon nanotubes (CNTs)/cotton ring spun yarns. CNTs and polypyrrole (PPy) were successfully embedded into the cotton yarns with a ply twist structure. The as-developed electrode exhibited excellent electrical conductivity (20 Ω/cm), good mechanical properties (59.8 MPa, 24.6%), a high specific capacitance of 386.5 mF/cm2 with the current density of 1 mA/cm2, and ideal cycle stability with the retention of 87.8% after 5000 cycles. Meanwhile, the assembled supercapacitor showed a power density of 278.4 μW/cm2 and an energy density of 13.21 μWh/cm2. It also presented outstanding capacitive performance under different angles. This facile ply twist method provided new possibilities for one-dimensional (1D) supercapacitor and flexible wearable electronics applications. [ABSTRACT FROM AUTHOR]

2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium methanesulfonate ([BHEM][mesy]) displayed good ability for separating cellulose from biomass material in previous works. In order to have a better understanding of the structure–property relationship and facilitate further potential applications in industry, it is necessary to obtain more data for the physicochemical properties of [BHEM][mesy] and its mixtures. In this work, the densities (ρ) and viscosities (η) of [BHEM][mesy] + solvents (water, methanol, ethanol, n-propanol and isopropanol) mixtures were measured at six temperatures from (298.15 to 323.15) K over the full molar composition range and fitted by an empirical quadratic equation and Vogel–Fucher–Tammann (VFT) equation. Moreover, the excess molar volumes (VE) and viscosity deviation (Δη) of five binary mixtures were calculated and correlated by the Redlich–Kister equation. In addition, the apparent molar volumes ( V φ ) and partial molar volumes ( V - ) of [BHEM][mesy] and solvents were also calculated and all these physicochemical property data (density, viscosity, excess molar properties as well as the apparent molar properties) are discussed in terms of the structure and interaction of binary mixtures. [ABSTRACT FROM AUTHOR]

A facile strategy for synthesizing MnCo2O4/carbon (MCO/C) composite nanofibers is introduced in this work, in which MCO nanoparticles with an average size of about 40 nm are distributed uniformly in carbon nanofiber matrix by electrospinning and subsequent heat treatment. When adopted as anode for lithium-ion batteries (LIBs), MCO/C exhibits better lithium storage capabilities in comparison with bare MCO. The initial discharge/charge capacity of MCO/C is up to 1484/1140 mAh g−1 and can maintain a stable capacity of 933 mAh g−1 at 100 mA g−1 over 200 cycles. Meanwhile, a reversible capacity of 500 mAh g−1 can be retained even at a high current density of 2 A g−1 after 1000 long cycles. The superior electrochemical properties are mainly resulted from the conductive carbon matrix which can not only promote electron transfer but also act as a buffer to alleviate volume change of MCO during the lithiation/delithiation process. It is demonstrated that MCO/C nanofiber can be used as prospective anode materials for LIBs. [ABSTRACT FROM AUTHOR]